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Source code for subprocess

# subprocess - Subprocesses with accessible I/O streams## For more information about this module, see PEP 324.## Copyright (c) 2003-2005 by Peter Astrand <astrand@lysator.liu.se>## Licensed to PSF under a Contributor Agreement.# See http://www.python.org/2.4/license for licensing details.r"""Subprocesses with accessible I/O streamsThis module allows you to spawn processes, connect to theirinput/output/error pipes, and obtain their return codes.For a complete description of this module see the Python documentation.Main API========run(...): Runs a command, waits for it to complete, then returns a CompletedProcess instance.Popen(...): A class for flexibly executing a command in a new processConstants---------DEVNULL: Special value that indicates that os.devnull should be usedPIPE: Special value that indicates a pipe should be createdSTDOUT: Special value that indicates that stderr should go to stdoutOlder API=========call(...): Runs a command, waits for it to complete, then returns the return code.check_call(...): Same as call() but raises CalledProcessError() if return code is not 0check_output(...): Same as check_call() but returns the contents of stdout instead of a return codegetoutput(...): Runs a command in the shell, waits for it to complete, then returns the outputgetstatusoutput(...): Runs a command in the shell, waits for it to complete, then returns a (status, output) tuple"""importsys_mswindows=(sys.platform=="win32")importioimportosimporttimeimportsignalimportbuiltinsimportwarningsimporterrnofromtimeimportmonotonicas_time# Exception classes used by this module.

[docs]classCalledProcessError(SubprocessError):"""Raised when run() is called with check=True and the process returns a non-zero exit status. Attributes: cmd, returncode, stdout, stderr, output """def__init__(self,returncode,cmd,output=None,stderr=None):self.returncode=returncodeself.cmd=cmdself.output=outputself.stderr=stderrdef__str__(self):ifself.returncodeandself.returncode<0:try:return"Command '%s' died with %r."%(self.cmd,signal.Signals(-self.returncode))exceptValueError:return"Command '%s' died with unknown signal %d."%(self.cmd,-self.returncode)else:return"Command '%s' returned non-zero exit status %d."%(self.cmd,self.returncode)@propertydefstdout(self):"""Alias for output attribute, to match stderr"""returnself.output@stdout.setterdefstdout(self,value):# There's no obvious reason to set this, but allow it anyway so# .stdout is a transparent alias for .outputself.output=value

[docs]classTimeoutExpired(SubprocessError):"""This exception is raised when the timeout expires while waiting for a child process. Attributes: cmd, output, stdout, stderr, timeout """def__init__(self,cmd,timeout,output=None,stderr=None):self.cmd=cmdself.timeout=timeoutself.output=outputself.stderr=stderrdef__str__(self):return("Command '%s' timed out after %s seconds"%(self.cmd,self.timeout))@propertydefstdout(self):returnself.output@stdout.setterdefstdout(self,value):# There's no obvious reason to set this, but allow it anyway so# .stdout is a transparent alias for .outputself.output=value

else:import_posixsubprocessimportselectimportselectorstry:importthreadingexceptImportError:importdummy_threadingasthreading# When select or poll has indicated that the file is writable,# we can write up to _PIPE_BUF bytes without risk of blocking.# POSIX defines PIPE_BUF as >= 512._PIPE_BUF=getattr(select,'PIPE_BUF',512)# poll/select have the advantage of not requiring any extra file# descriptor, contrarily to epoll/kqueue (also, they require a single# syscall).ifhasattr(selectors,'PollSelector'):_PopenSelector=selectors.PollSelectorelse:_PopenSelector=selectors.SelectSelector__all__=["Popen","PIPE","STDOUT","call","check_call","getstatusoutput","getoutput","check_output","run","CalledProcessError","DEVNULL","SubprocessError","TimeoutExpired","CompletedProcess"]# NOTE: We intentionally exclude list2cmdline as it is# considered an internal implementation detail. issue10838.if_mswindows:from_winapiimport(CREATE_NEW_CONSOLE,CREATE_NEW_PROCESS_GROUP,STD_INPUT_HANDLE,STD_OUTPUT_HANDLE,STD_ERROR_HANDLE,SW_HIDE,STARTF_USESTDHANDLES,STARTF_USESHOWWINDOW)__all__.extend(["CREATE_NEW_CONSOLE","CREATE_NEW_PROCESS_GROUP","STD_INPUT_HANDLE","STD_OUTPUT_HANDLE","STD_ERROR_HANDLE","SW_HIDE","STARTF_USESTDHANDLES","STARTF_USESHOWWINDOW","STARTUPINFO"])classHandle(int):closed=FalsedefClose(self,CloseHandle=_winapi.CloseHandle):ifnotself.closed:self.closed=TrueCloseHandle(self)defDetach(self):ifnotself.closed:self.closed=Truereturnint(self)raiseValueError("already closed")def__repr__(self):return"%s(%d)"%(self.__class__.__name__,int(self))__del__=Close__str__=__repr__# This lists holds Popen instances for which the underlying process had not# exited at the time its __del__ method got called: those processes are wait()ed# for synchronously from _cleanup() when a new Popen object is created, to avoid# zombie processes._active=[]def_cleanup():forinstin_active[:]:res=inst._internal_poll(_deadstate=sys.maxsize)ifresisnotNone:try:_active.remove(inst)exceptValueError:# This can happen if two threads create a new Popen instance.# It's harmless that it was already removed, so ignore.passPIPE=-1STDOUT=-2DEVNULL=-3# XXX This function is only used by multiprocessing and the test suite,# but it's here so that it can be imported when Python is compiled without# threads.def_optim_args_from_interpreter_flags():"""Return a list of command-line arguments reproducing the current optimization settings in sys.flags."""args=[]value=sys.flags.optimizeifvalue>0:args.append('-'+'O'*value)returnargsdef_args_from_interpreter_flags():"""Return a list of command-line arguments reproducing the current settings in sys.flags and sys.warnoptions."""flag_opt_map={'debug':'d',# 'inspect': 'i',# 'interactive': 'i','dont_write_bytecode':'B','no_user_site':'s','no_site':'S','ignore_environment':'E','verbose':'v','bytes_warning':'b','quiet':'q',# -O is handled in _optim_args_from_interpreter_flags()}args=_optim_args_from_interpreter_flags()forflag,optinflag_opt_map.items():v=getattr(sys.flags,flag)ifv>0:args.append('-'+opt*v)foroptinsys.warnoptions:args.append('-W'+opt)returnargs

[docs]defcall(*popenargs,timeout=None,**kwargs):"""Run command with arguments. Wait for command to complete or timeout, then return the returncode attribute. The arguments are the same as for the Popen constructor. Example: retcode = call(["ls", "-l"]) """withPopen(*popenargs,**kwargs)asp:try:returnp.wait(timeout=timeout)except:p.kill()p.wait()raise

[docs]defcheck_call(*popenargs,**kwargs):"""Run command with arguments. Wait for command to complete. If the exit code was zero then return, otherwise raise CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute. The arguments are the same as for the call function. Example: check_call(["ls", "-l"]) """retcode=call(*popenargs,**kwargs)ifretcode:cmd=kwargs.get("args")ifcmdisNone:cmd=popenargs[0]raiseCalledProcessError(retcode,cmd)return0

[docs]defcheck_output(*popenargs,timeout=None,**kwargs):r"""Run command with arguments and return its output. If the exit code was non-zero it raises a CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute and output in the output attribute. The arguments are the same as for the Popen constructor. Example: >>> check_output(["ls", "-l", "/dev/null"]) b'crw-rw-rw- 1 root root 1, 3 Oct 18 2007 /dev/null\n' The stdout argument is not allowed as it is used internally. To capture standard error in the result, use stderr=STDOUT. >>> check_output(["/bin/sh", "-c", ... "ls -l non_existent_file ; exit 0"], ... stderr=STDOUT) b'ls: non_existent_file: No such file or directory\n' There is an additional optional argument, "input", allowing you to pass a string to the subprocess's stdin. If you use this argument you may not also use the Popen constructor's "stdin" argument, as it too will be used internally. Example: >>> check_output(["sed", "-e", "s/foo/bar/"], ... input=b"when in the course of fooman events\n") b'when in the course of barman events\n' If universal_newlines=True is passed, the "input" argument must be a string and the return value will be a string rather than bytes. """if'stdout'inkwargs:raiseValueError('stdout argument not allowed, it will be overridden.')if'input'inkwargsandkwargs['input']isNone:# Explicitly passing input=None was previously equivalent to passing an# empty string. That is maintained here for backwards compatibility.kwargs['input']=''ifkwargs.get('universal_newlines',False)elseb''returnrun(*popenargs,stdout=PIPE,timeout=timeout,check=True,**kwargs).stdout

classCompletedProcess(object):"""A process that has finished running. This is returned by run(). Attributes: args: The list or str args passed to run(). returncode: The exit code of the process, negative for signals. stdout: The standard output (None if not captured). stderr: The standard error (None if not captured). """def__init__(self,args,returncode,stdout=None,stderr=None):self.args=argsself.returncode=returncodeself.stdout=stdoutself.stderr=stderrdef__repr__(self):args=['args={!r}'.format(self.args),'returncode={!r}'.format(self.returncode)]ifself.stdoutisnotNone:args.append('stdout={!r}'.format(self.stdout))ifself.stderrisnotNone:args.append('stderr={!r}'.format(self.stderr))return"{}({})".format(type(self).__name__,', '.join(args))defcheck_returncode(self):"""Raise CalledProcessError if the exit code is non-zero."""ifself.returncode:raiseCalledProcessError(self.returncode,self.args,self.stdout,self.stderr)defrun(*popenargs,input=None,timeout=None,check=False,**kwargs):"""Run command with arguments and return a CompletedProcess instance. The returned instance will have attributes args, returncode, stdout and stderr. By default, stdout and stderr are not captured, and those attributes will be None. Pass stdout=PIPE and/or stderr=PIPE in order to capture them. If check is True and the exit code was non-zero, it raises a CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute, and output & stderr attributes if those streams were captured. If timeout is given, and the process takes too long, a TimeoutExpired exception will be raised. There is an optional argument "input", allowing you to pass a string to the subprocess's stdin. If you use this argument you may not also use the Popen constructor's "stdin" argument, as it will be used internally. The other arguments are the same as for the Popen constructor. If universal_newlines=True is passed, the "input" argument must be a string and stdout/stderr in the returned object will be strings rather than bytes. """ifinputisnotNone:if'stdin'inkwargs:raiseValueError('stdin and input arguments may not both be used.')kwargs['stdin']=PIPEwithPopen(*popenargs,**kwargs)asprocess:try:stdout,stderr=process.communicate(input,timeout=timeout)exceptTimeoutExpired:process.kill()stdout,stderr=process.communicate()raiseTimeoutExpired(process.args,timeout,output=stdout,stderr=stderr)except:process.kill()process.wait()raiseretcode=process.poll()ifcheckandretcode:raiseCalledProcessError(retcode,process.args,output=stdout,stderr=stderr)returnCompletedProcess(process.args,retcode,stdout,stderr)deflist2cmdline(seq):""" Translate a sequence of arguments into a command line string, using the same rules as the MS C runtime: 1) Arguments are delimited by white space, which is either a space or a tab. 2) A string surrounded by double quotation marks is interpreted as a single argument, regardless of white space contained within. A quoted string can be embedded in an argument. 3) A double quotation mark preceded by a backslash is interpreted as a literal double quotation mark. 4) Backslashes are interpreted literally, unless they immediately precede a double quotation mark. 5) If backslashes immediately precede a double quotation mark, every pair of backslashes is interpreted as a literal backslash. If the number of backslashes is odd, the last backslash escapes the next double quotation mark as described in rule 3. """# See# http://msdn.microsoft.com/en-us/library/17w5ykft.aspx# or search http://msdn.microsoft.com for# "Parsing C++ Command-Line Arguments"result=[]needquote=Falseforarginseq:bs_buf=[]# Add a space to separate this argument from the othersifresult:result.append(' ')needquote=(" "inarg)or("\t"inarg)ornotargifneedquote:result.append('"')forcinarg:ifc=='\\':# Don't know if we need to double yet.bs_buf.append(c)elifc=='"':# Double backslashes.result.append('\\'*len(bs_buf)*2)bs_buf=[]result.append('\\"')else:# Normal charifbs_buf:result.extend(bs_buf)bs_buf=[]result.append(c)# Add remaining backslashes, if any.ifbs_buf:result.extend(bs_buf)ifneedquote:result.extend(bs_buf)result.append('"')return''.join(result)# Various tools for executing commands and looking at their output and status.#

[docs]defgetstatusoutput(cmd):""" Return (status, output) of executing cmd in a shell. Execute the string 'cmd' in a shell with 'check_output' and return a 2-tuple (status, output). The locale encoding is used to decode the output and process newlines. A trailing newline is stripped from the output. The exit status for the command can be interpreted according to the rules for the function 'wait'. Example: >>> import subprocess >>> subprocess.getstatusoutput('ls /bin/ls') (0, '/bin/ls') >>> subprocess.getstatusoutput('cat /bin/junk') (256, 'cat: /bin/junk: No such file or directory') >>> subprocess.getstatusoutput('/bin/junk') (256, 'sh: /bin/junk: not found') """try:data=check_output(cmd,shell=True,universal_newlines=True,stderr=STDOUT)status=0exceptCalledProcessErrorasex:data=ex.outputstatus=ex.returncodeifdata[-1:]=='\n':data=data[:-1]returnstatus,data

[docs]defgetoutput(cmd):"""Return output (stdout or stderr) of executing cmd in a shell. Like getstatusoutput(), except the exit status is ignored and the return value is a string containing the command's output. Example: >>> import subprocess >>> subprocess.getoutput('ls /bin/ls') '/bin/ls' """returngetstatusoutput(cmd)[1]

_PLATFORM_DEFAULT_CLOSE_FDS=object()

[docs]classPopen(object):""" Execute a child program in a new process. For a complete description of the arguments see the Python documentation. Arguments: args: A string, or a sequence of program arguments. bufsize: supplied as the buffering argument to the open() function when creating the stdin/stdout/stderr pipe file objects executable: A replacement program to execute. stdin, stdout and stderr: These specify the executed programs' standard input, standard output and standard error file handles, respectively. preexec_fn: (POSIX only) An object to be called in the child process just before the child is executed. close_fds: Controls closing or inheriting of file descriptors. shell: If true, the command will be executed through the shell. cwd: Sets the current directory before the child is executed. env: Defines the environment variables for the new process. universal_newlines: If true, use universal line endings for file objects stdin, stdout and stderr. startupinfo and creationflags (Windows only) restore_signals (POSIX only) start_new_session (POSIX only) pass_fds (POSIX only) encoding and errors: Text mode encoding and error handling to use for file objects stdin, stdout and stderr. Attributes: stdin, stdout, stderr, pid, returncode """_child_created=False# Set here since __del__ checks itdef__init__(self,args,bufsize=-1,executable=None,stdin=None,stdout=None,stderr=None,preexec_fn=None,close_fds=_PLATFORM_DEFAULT_CLOSE_FDS,shell=False,cwd=None,env=None,universal_newlines=False,startupinfo=None,creationflags=0,restore_signals=True,start_new_session=False,pass_fds=(),*,encoding=None,errors=None):"""Create new Popen instance."""_cleanup()# Held while anything is calling waitpid before returncode has been# updated to prevent clobbering returncode if wait() or poll() are# called from multiple threads at once. After acquiring the lock,# code must re-check self.returncode to see if another thread just# finished a waitpid() call.self._waitpid_lock=threading.Lock()self._input=Noneself._communication_started=FalseifbufsizeisNone:bufsize=-1# Restore defaultifnotisinstance(bufsize,int):raiseTypeError("bufsize must be an integer")if_mswindows:ifpreexec_fnisnotNone:raiseValueError("preexec_fn is not supported on Windows ""platforms")any_stdio_set=(stdinisnotNoneorstdoutisnotNoneorstderrisnotNone)ifclose_fdsis_PLATFORM_DEFAULT_CLOSE_FDS:ifany_stdio_set:close_fds=Falseelse:close_fds=Trueelifclose_fdsandany_stdio_set:raiseValueError("close_fds is not supported on Windows platforms"" if you redirect stdin/stdout/stderr")else:# POSIXifclose_fdsis_PLATFORM_DEFAULT_CLOSE_FDS:close_fds=Trueifpass_fdsandnotclose_fds:warnings.warn("pass_fds overriding close_fds.",RuntimeWarning)close_fds=TrueifstartupinfoisnotNone:raiseValueError("startupinfo is only supported on Windows ""platforms")ifcreationflags!=0:raiseValueError("creationflags is only supported on Windows ""platforms")self.args=argsself.stdin=Noneself.stdout=Noneself.stderr=Noneself.pid=Noneself.returncode=Noneself.universal_newlines=universal_newlinesself.encoding=encodingself.errors=errors# Input and output objects. The general principle is like# this:## Parent Child# ------ -----# p2cwrite ---stdin---> p2cread# c2pread <--stdout--- c2pwrite# errread <--stderr--- errwrite## On POSIX, the child objects are file descriptors. On# Windows, these are Windows file handles. The parent objects# are file descriptors on both platforms. The parent objects# are -1 when not using PIPEs. The child objects are -1# when not redirecting.(p2cread,p2cwrite,c2pread,c2pwrite,errread,errwrite)=self._get_handles(stdin,stdout,stderr)# We wrap OS handles *before* launching the child, otherwise a# quickly terminating child could make our fds unwrappable# (see #8458).if_mswindows:ifp2cwrite!=-1:p2cwrite=msvcrt.open_osfhandle(p2cwrite.Detach(),0)ifc2pread!=-1:c2pread=msvcrt.open_osfhandle(c2pread.Detach(),0)iferrread!=-1:errread=msvcrt.open_osfhandle(errread.Detach(),0)text_mode=encodingorerrorsoruniversal_newlinesself._closed_child_pipe_fds=Falsetry:ifp2cwrite!=-1:self.stdin=io.open(p2cwrite,'wb',bufsize)iftext_mode:self.stdin=io.TextIOWrapper(self.stdin,write_through=True,line_buffering=(bufsize==1),encoding=encoding,errors=errors)ifc2pread!=-1:self.stdout=io.open(c2pread,'rb',bufsize)iftext_mode:self.stdout=io.TextIOWrapper(self.stdout,encoding=encoding,errors=errors)iferrread!=-1:self.stderr=io.open(errread,'rb',bufsize)iftext_mode:self.stderr=io.TextIOWrapper(self.stderr,encoding=encoding,errors=errors)self._execute_child(args,executable,preexec_fn,close_fds,pass_fds,cwd,env,startupinfo,creationflags,shell,p2cread,p2cwrite,c2pread,c2pwrite,errread,errwrite,restore_signals,start_new_session)except:# Cleanup if the child failed starting.forfinfilter(None,(self.stdin,self.stdout,self.stderr)):try:f.close()exceptOSError:pass# Ignore EBADF or other errors.ifnotself._closed_child_pipe_fds:to_close=[]ifstdin==PIPE:to_close.append(p2cread)ifstdout==PIPE:to_close.append(c2pwrite)ifstderr==PIPE:to_close.append(errwrite)ifhasattr(self,'_devnull'):to_close.append(self._devnull)forfdinto_close:try:os.close(fd)exceptOSError:passraisedef_translate_newlines(self,data,encoding,errors):data=data.decode(encoding,errors)returndata.replace("\r\n","\n").replace("\r","\n")def__enter__(self):returnselfdef__exit__(self,type,value,traceback):ifself.stdout:self.stdout.close()ifself.stderr:self.stderr.close()try:# Flushing a BufferedWriter may raise an errorifself.stdin:self.stdin.close()finally:# Wait for the process to terminate, to avoid zombies.self.wait()def__del__(self,_maxsize=sys.maxsize):ifnotself._child_created:# We didn't get to successfully create a child process.returnifself.returncodeisNone:# Not reading subprocess exit status creates a zombi process which# is only destroyed at the parent python process exitwarnings.warn("subprocess %s is still running"%self.pid,ResourceWarning,source=self)# In case the child hasn't been waited on, check if it's done.self._internal_poll(_deadstate=_maxsize)ifself.returncodeisNoneand_activeisnotNone:# Child is still running, keep us alive until we can wait on it._active.append(self)def_get_devnull(self):ifnothasattr(self,'_devnull'):self._devnull=os.open(os.devnull,os.O_RDWR)returnself._devnulldef_stdin_write(self,input):ifinput:try:self.stdin.write(input)exceptBrokenPipeError:pass# communicate() must ignore broken pipe errors.exceptOSErrorase:ife.errno==errno.EINVALandself.poll()isnotNone:# Issue #19612: On Windows, stdin.write() fails with EINVAL# if the process already exited before the writepasselse:raisetry:self.stdin.close()exceptBrokenPipeError:pass# communicate() must ignore broken pipe errors.exceptOSErrorase:ife.errno==errno.EINVALandself.poll()isnotNone:passelse:raise

[docs]defcommunicate(self,input=None,timeout=None):"""Interact with process: Send data to stdin. Read data from stdout and stderr, until end-of-file is reached. Wait for process to terminate. The optional "input" argument should be data to be sent to the child process (if self.universal_newlines is True, this should be a string; if it is False, "input" should be bytes), or None, if no data should be sent to the child. communicate() returns a tuple (stdout, stderr). These will be bytes or, if self.universal_newlines was True, a string. """ifself._communication_startedandinput:raiseValueError("Cannot send input after starting communication")# Optimization: If we are not worried about timeouts, we haven't# started communicating, and we have one or zero pipes, using select()# or threads is unnecessary.if(timeoutisNoneandnotself._communication_startedand[self.stdin,self.stdout,self.stderr].count(None)>=2):stdout=Nonestderr=Noneifself.stdin:self._stdin_write(input)elifself.stdout:stdout=self.stdout.read()self.stdout.close()elifself.stderr:stderr=self.stderr.read()self.stderr.close()self.wait()else:iftimeoutisnotNone:endtime=_time()+timeoutelse:endtime=Nonetry:stdout,stderr=self._communicate(input,endtime,timeout)finally:self._communication_started=Truests=self.wait(timeout=self._remaining_time(endtime))return(stdout,stderr)

[docs]defpoll(self):"""Check if child process has terminated. Set and return returncode attribute."""returnself._internal_poll()

def_remaining_time(self,endtime):"""Convenience for _communicate when computing timeouts."""ifendtimeisNone:returnNoneelse:returnendtime-_time()def_check_timeout(self,endtime,orig_timeout):"""Convenience for checking if a timeout has expired."""ifendtimeisNone:returnif_time()>endtime:raiseTimeoutExpired(self.args,orig_timeout)if_mswindows:## Windows methods#def_get_handles(self,stdin,stdout,stderr):"""Construct and return tuple with IO objects: p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite """ifstdinisNoneandstdoutisNoneandstderrisNone:return(-1,-1,-1,-1,-1,-1)p2cread,p2cwrite=-1,-1c2pread,c2pwrite=-1,-1errread,errwrite=-1,-1ifstdinisNone:p2cread=_winapi.GetStdHandle(_winapi.STD_INPUT_HANDLE)ifp2creadisNone:p2cread,_=_winapi.CreatePipe(None,0)p2cread=Handle(p2cread)_winapi.CloseHandle(_)elifstdin==PIPE:p2cread,p2cwrite=_winapi.CreatePipe(None,0)p2cread,p2cwrite=Handle(p2cread),Handle(p2cwrite)elifstdin==DEVNULL:p2cread=msvcrt.get_osfhandle(self._get_devnull())elifisinstance(stdin,int):p2cread=msvcrt.get_osfhandle(stdin)else:# Assuming file-like objectp2cread=msvcrt.get_osfhandle(stdin.fileno())p2cread=self._make_inheritable(p2cread)ifstdoutisNone:c2pwrite=_winapi.GetStdHandle(_winapi.STD_OUTPUT_HANDLE)ifc2pwriteisNone:_,c2pwrite=_winapi.CreatePipe(None,0)c2pwrite=Handle(c2pwrite)_winapi.CloseHandle(_)elifstdout==PIPE:c2pread,c2pwrite=_winapi.CreatePipe(None,0)c2pread,c2pwrite=Handle(c2pread),Handle(c2pwrite)elifstdout==DEVNULL:c2pwrite=msvcrt.get_osfhandle(self._get_devnull())elifisinstance(stdout,int):c2pwrite=msvcrt.get_osfhandle(stdout)else:# Assuming file-like objectc2pwrite=msvcrt.get_osfhandle(stdout.fileno())c2pwrite=self._make_inheritable(c2pwrite)ifstderrisNone:errwrite=_winapi.GetStdHandle(_winapi.STD_ERROR_HANDLE)iferrwriteisNone:_,errwrite=_winapi.CreatePipe(None,0)errwrite=Handle(errwrite)_winapi.CloseHandle(_)elifstderr==PIPE:errread,errwrite=_winapi.CreatePipe(None,0)errread,errwrite=Handle(errread),Handle(errwrite)elifstderr==STDOUT:errwrite=c2pwriteelifstderr==DEVNULL:errwrite=msvcrt.get_osfhandle(self._get_devnull())elifisinstance(stderr,int):errwrite=msvcrt.get_osfhandle(stderr)else:# Assuming file-like objecterrwrite=msvcrt.get_osfhandle(stderr.fileno())errwrite=self._make_inheritable(errwrite)return(p2cread,p2cwrite,c2pread,c2pwrite,errread,errwrite)def_make_inheritable(self,handle):"""Return a duplicate of handle, which is inheritable"""h=_winapi.DuplicateHandle(_winapi.GetCurrentProcess(),handle,_winapi.GetCurrentProcess(),0,1,_winapi.DUPLICATE_SAME_ACCESS)returnHandle(h)def_execute_child(self,args,executable,preexec_fn,close_fds,pass_fds,cwd,env,startupinfo,creationflags,shell,p2cread,p2cwrite,c2pread,c2pwrite,errread,errwrite,unused_restore_signals,unused_start_new_session):"""Execute program (MS Windows version)"""assertnotpass_fds,"pass_fds not supported on Windows."ifnotisinstance(args,str):args=list2cmdline(args)# Process startup detailsifstartupinfoisNone:startupinfo=STARTUPINFO()if-1notin(p2cread,c2pwrite,errwrite):startupinfo.dwFlags|=_winapi.STARTF_USESTDHANDLESstartupinfo.hStdInput=p2creadstartupinfo.hStdOutput=c2pwritestartupinfo.hStdError=errwriteifshell:startupinfo.dwFlags|=_winapi.STARTF_USESHOWWINDOWstartupinfo.wShowWindow=_winapi.SW_HIDEcomspec=os.environ.get("COMSPEC","cmd.exe")args='{} /c "{}"'.format(comspec,args)# Start the processtry:hp,ht,pid,tid=_winapi.CreateProcess(executable,args,# no special securityNone,None,int(notclose_fds),creationflags,env,cwd,startupinfo)finally:# Child is launched. Close the parent's copy of those pipe# handles that only the child should have open. You need# to make sure that no handles to the write end of the# output pipe are maintained in this process or else the# pipe will not close when the child process exits and the# ReadFile will hang.ifp2cread!=-1:p2cread.Close()ifc2pwrite!=-1:c2pwrite.Close()iferrwrite!=-1:errwrite.Close()ifhasattr(self,'_devnull'):os.close(self._devnull)# Retain the process handle, but close the thread handleself._child_created=Trueself._handle=Handle(hp)self.pid=pid_winapi.CloseHandle(ht)def_internal_poll(self,_deadstate=None,_WaitForSingleObject=_winapi.WaitForSingleObject,_WAIT_OBJECT_0=_winapi.WAIT_OBJECT_0,_GetExitCodeProcess=_winapi.GetExitCodeProcess):"""Check if child process has terminated. Returns returncode attribute. This method is called by __del__, so it can only refer to objects in its local scope. """ifself.returncodeisNone:if_WaitForSingleObject(self._handle,0)==_WAIT_OBJECT_0:self.returncode=_GetExitCodeProcess(self._handle)returnself.returncodedefwait(self,timeout=None,endtime=None):"""Wait for child process to terminate. Returns returncode attribute."""ifendtimeisnotNone:warnings.warn("'endtime' argument is deprecated; use 'timeout'.",DeprecationWarning,stacklevel=2)timeout=self._remaining_time(endtime)iftimeoutisNone:timeout_millis=_winapi.INFINITEelse:timeout_millis=int(timeout*1000)ifself.returncodeisNone:result=_winapi.WaitForSingleObject(self._handle,timeout_millis)ifresult==_winapi.WAIT_TIMEOUT:raiseTimeoutExpired(self.args,timeout)self.returncode=_winapi.GetExitCodeProcess(self._handle)returnself.returncodedef_readerthread(self,fh,buffer):buffer.append(fh.read())fh.close()def_communicate(self,input,endtime,orig_timeout):# Start reader threads feeding into a list hanging off of this# object, unless they've already been started.ifself.stdoutandnothasattr(self,"_stdout_buff"):self._stdout_buff=[]self.stdout_thread= \
threading.Thread(target=self._readerthread,args=(self.stdout,self._stdout_buff))self.stdout_thread.daemon=Trueself.stdout_thread.start()ifself.stderrandnothasattr(self,"_stderr_buff"):self._stderr_buff=[]self.stderr_thread= \
threading.Thread(target=self._readerthread,args=(self.stderr,self._stderr_buff))self.stderr_thread.daemon=Trueself.stderr_thread.start()ifself.stdin:self._stdin_write(input)# Wait for the reader threads, or time out. If we time out, the# threads remain reading and the fds left open in case the user# calls communicate again.ifself.stdoutisnotNone:self.stdout_thread.join(self._remaining_time(endtime))ifself.stdout_thread.is_alive():raiseTimeoutExpired(self.args,orig_timeout)ifself.stderrisnotNone:self.stderr_thread.join(self._remaining_time(endtime))ifself.stderr_thread.is_alive():raiseTimeoutExpired(self.args,orig_timeout)# Collect the output from and close both pipes, now that we know# both have been read successfully.stdout=Nonestderr=Noneifself.stdout:stdout=self._stdout_buffself.stdout.close()ifself.stderr:stderr=self._stderr_buffself.stderr.close()# All data exchanged. Translate lists into strings.ifstdoutisnotNone:stdout=stdout[0]ifstderrisnotNone:stderr=stderr[0]return(stdout,stderr)defsend_signal(self,sig):"""Send a signal to the process."""# Don't signal a process that we know has already died.ifself.returncodeisnotNone:returnifsig==signal.SIGTERM:self.terminate()elifsig==signal.CTRL_C_EVENT:os.kill(self.pid,signal.CTRL_C_EVENT)elifsig==signal.CTRL_BREAK_EVENT:os.kill(self.pid,signal.CTRL_BREAK_EVENT)else:raiseValueError("Unsupported signal: {}".format(sig))defterminate(self):"""Terminates the process."""# Don't terminate a process that we know has already died.ifself.returncodeisnotNone:returntry:_winapi.TerminateProcess(self._handle,1)exceptPermissionError:# ERROR_ACCESS_DENIED (winerror 5) is received when the# process already died.rc=_winapi.GetExitCodeProcess(self._handle)ifrc==_winapi.STILL_ACTIVE:raiseself.returncode=rckill=terminateelse:## POSIX methods#def_get_handles(self,stdin,stdout,stderr):"""Construct and return tuple with IO objects: p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite """p2cread,p2cwrite=-1,-1c2pread,c2pwrite=-1,-1errread,errwrite=-1,-1ifstdinisNone:passelifstdin==PIPE:p2cread,p2cwrite=os.pipe()elifstdin==DEVNULL:p2cread=self._get_devnull()elifisinstance(stdin,int):p2cread=stdinelse:# Assuming file-like objectp2cread=stdin.fileno()ifstdoutisNone:passelifstdout==PIPE:c2pread,c2pwrite=os.pipe()elifstdout==DEVNULL:c2pwrite=self._get_devnull()elifisinstance(stdout,int):c2pwrite=stdoutelse:# Assuming file-like objectc2pwrite=stdout.fileno()ifstderrisNone:passelifstderr==PIPE:errread,errwrite=os.pipe()elifstderr==STDOUT:ifc2pwrite!=-1:errwrite=c2pwriteelse:# child's stdout is not set, use parent's stdouterrwrite=sys.__stdout__.fileno()elifstderr==DEVNULL:errwrite=self._get_devnull()elifisinstance(stderr,int):errwrite=stderrelse:# Assuming file-like objecterrwrite=stderr.fileno()return(p2cread,p2cwrite,c2pread,c2pwrite,errread,errwrite)def_execute_child(self,args,executable,preexec_fn,close_fds,pass_fds,cwd,env,startupinfo,creationflags,shell,p2cread,p2cwrite,c2pread,c2pwrite,errread,errwrite,restore_signals,start_new_session):"""Execute program (POSIX version)"""ifisinstance(args,(str,bytes)):args=[args]else:args=list(args)ifshell:args=["/bin/sh","-c"]+argsifexecutable:args[0]=executableifexecutableisNone:executable=args[0]orig_executable=executable# For transferring possible exec failure from child to parent.# Data format: "exception name:hex errno:description"# Pickle is not used; it is complex and involves memory allocation.errpipe_read,errpipe_write=os.pipe()# errpipe_write must not be in the standard io 0, 1, or 2 fd range.low_fds_to_close=[]whileerrpipe_write<3:low_fds_to_close.append(errpipe_write)errpipe_write=os.dup(errpipe_write)forlow_fdinlow_fds_to_close:os.close(low_fd)try:try:# We must avoid complex work that could involve# malloc or free in the child process to avoid# potential deadlocks, thus we do all this here.# and pass it to fork_exec()ifenvisnotNone:env_list=[os.fsencode(k)+b'='+os.fsencode(v)fork,vinenv.items()]else:env_list=None# Use execv instead of execve.executable=os.fsencode(executable)ifos.path.dirname(executable):executable_list=(executable,)else:# This matches the behavior of os._execvpe().executable_list=tuple(os.path.join(os.fsencode(dir),executable)fordirinos.get_exec_path(env))fds_to_keep=set(pass_fds)fds_to_keep.add(errpipe_write)self.pid=_posixsubprocess.fork_exec(args,executable_list,close_fds,sorted(fds_to_keep),cwd,env_list,p2cread,p2cwrite,c2pread,c2pwrite,errread,errwrite,errpipe_read,errpipe_write,restore_signals,start_new_session,preexec_fn)self._child_created=Truefinally:# be sure the FD is closed no matter whatos.close(errpipe_write)# self._devnull is not always defined.devnull_fd=getattr(self,'_devnull',None)ifp2cread!=-1andp2cwrite!=-1andp2cread!=devnull_fd:os.close(p2cread)ifc2pwrite!=-1andc2pread!=-1andc2pwrite!=devnull_fd:os.close(c2pwrite)iferrwrite!=-1anderrread!=-1anderrwrite!=devnull_fd:os.close(errwrite)ifdevnull_fdisnotNone:os.close(devnull_fd)# Prevent a double close of these fds from __init__ on error.self._closed_child_pipe_fds=True# Wait for exec to fail or succeed; possibly raising an# exception (limited in size)errpipe_data=bytearray()whileTrue:part=os.read(errpipe_read,50000)errpipe_data+=partifnotpartorlen(errpipe_data)>50000:breakfinally:# be sure the FD is closed no matter whatos.close(errpipe_read)iferrpipe_data:try:pid,sts=os.waitpid(self.pid,0)ifpid==self.pid:self._handle_exitstatus(sts)else:self.returncode=sys.maxsizeexceptChildProcessError:passtry:exception_name,hex_errno,err_msg=(errpipe_data.split(b':',2))exceptValueError:exception_name=b'SubprocessError'hex_errno=b'0'err_msg=(b'Bad exception data from child: '+repr(errpipe_data))child_exception_type=getattr(builtins,exception_name.decode('ascii'),SubprocessError)err_msg=err_msg.decode(errors="surrogatepass")ifissubclass(child_exception_type,OSError)andhex_errno:errno_num=int(hex_errno,16)child_exec_never_called=(err_msg=="noexec")ifchild_exec_never_called:err_msg=""iferrno_num!=0:err_msg=os.strerror(errno_num)iferrno_num==errno.ENOENT:ifchild_exec_never_called:# The error must be from chdir(cwd).err_msg+=': '+repr(cwd)else:err_msg+=': '+repr(orig_executable)raisechild_exception_type(errno_num,err_msg)raisechild_exception_type(err_msg)def_handle_exitstatus(self,sts,_WIFSIGNALED=os.WIFSIGNALED,_WTERMSIG=os.WTERMSIG,_WIFEXITED=os.WIFEXITED,_WEXITSTATUS=os.WEXITSTATUS):"""All callers to this function MUST hold self._waitpid_lock."""# This method is called (indirectly) by __del__, so it cannot# refer to anything outside of its local scope.if_WIFSIGNALED(sts):self.returncode=-_WTERMSIG(sts)elif_WIFEXITED(sts):self.returncode=_WEXITSTATUS(sts)else:# Should never happenraiseSubprocessError("Unknown child exit status!")def_internal_poll(self,_deadstate=None,_waitpid=os.waitpid,_WNOHANG=os.WNOHANG,_ECHILD=errno.ECHILD):"""Check if child process has terminated. Returns returncode attribute. This method is called by __del__, so it cannot reference anything outside of the local scope (nor can any methods it calls). """ifself.returncodeisNone:ifnotself._waitpid_lock.acquire(False):# Something else is busy calling waitpid. Don't allow two# at once. We know nothing yet.returnNonetry:ifself.returncodeisnotNone:returnself.returncode# Another thread waited.pid,sts=_waitpid(self.pid,_WNOHANG)ifpid==self.pid:self._handle_exitstatus(sts)exceptOSErrorase:if_deadstateisnotNone:self.returncode=_deadstateelife.errno==_ECHILD:# This happens if SIGCLD is set to be ignored or# waiting for child processes has otherwise been# disabled for our process. This child is dead, we# can't get the status.# http://bugs.python.org/issue15756self.returncode=0finally:self._waitpid_lock.release()returnself.returncodedef_try_wait(self,wait_flags):"""All callers to this function MUST hold self._waitpid_lock."""try:(pid,sts)=os.waitpid(self.pid,wait_flags)exceptChildProcessError:# This happens if SIGCLD is set to be ignored or waiting# for child processes has otherwise been disabled for our# process. This child is dead, we can't get the status.pid=self.pidsts=0return(pid,sts)

[docs]defwait(self,timeout=None,endtime=None):"""Wait for child process to terminate. Returns returncode attribute."""ifself.returncodeisnotNone:returnself.returncodeifendtimeisnotNone:warnings.warn("'endtime' argument is deprecated; use 'timeout'.",DeprecationWarning,stacklevel=2)ifendtimeisnotNoneortimeoutisnotNone:ifendtimeisNone:endtime=_time()+timeouteliftimeoutisNone:timeout=self._remaining_time(endtime)ifendtimeisnotNone:# Enter a busy loop if we have a timeout. This busy loop was# cribbed from Lib/threading.py in Thread.wait() at r71065.delay=0.0005# 500 us -> initial delay of 1 mswhileTrue:ifself._waitpid_lock.acquire(False):try:ifself.returncodeisnotNone:break# Another thread waited.(pid,sts)=self._try_wait(os.WNOHANG)assertpid==self.pidorpid==0ifpid==self.pid:self._handle_exitstatus(sts)breakfinally:self._waitpid_lock.release()remaining=self._remaining_time(endtime)ifremaining<=0:raiseTimeoutExpired(self.args,timeout)delay=min(delay*2,remaining,.05)time.sleep(delay)else:whileself.returncodeisNone:withself._waitpid_lock:ifself.returncodeisnotNone:break# Another thread waited.(pid,sts)=self._try_wait(0)# Check the pid and loop as waitpid has been known to# return 0 even without WNOHANG in odd situations.# http://bugs.python.org/issue14396.ifpid==self.pid:self._handle_exitstatus(sts)returnself.returncode

def_communicate(self,input,endtime,orig_timeout):ifself.stdinandnotself._communication_started:# Flush stdio buffer. This might block, if the user has# been writing to .stdin in an uncontrolled fashion.try:self.stdin.flush()exceptBrokenPipeError:pass# communicate() must ignore BrokenPipeError.ifnotinput:try:self.stdin.close()exceptBrokenPipeError:pass# communicate() must ignore BrokenPipeError.stdout=Nonestderr=None# Only create this mapping if we haven't already.ifnotself._communication_started:self._fileobj2output={}ifself.stdout:self._fileobj2output[self.stdout]=[]ifself.stderr:self._fileobj2output[self.stderr]=[]ifself.stdout:stdout=self._fileobj2output[self.stdout]ifself.stderr:stderr=self._fileobj2output[self.stderr]self._save_input(input)ifself._input:input_view=memoryview(self._input)with_PopenSelector()asselector:ifself.stdinandinput:selector.register(self.stdin,selectors.EVENT_WRITE)ifself.stdout:selector.register(self.stdout,selectors.EVENT_READ)ifself.stderr:selector.register(self.stderr,selectors.EVENT_READ)whileselector.get_map():timeout=self._remaining_time(endtime)iftimeoutisnotNoneandtimeout<0:raiseTimeoutExpired(self.args,orig_timeout)ready=selector.select(timeout)self._check_timeout(endtime,orig_timeout)# XXX Rewrite these to use non-blocking I/O on the file# objects; they are no longer using C stdio!forkey,eventsinready:ifkey.fileobjisself.stdin:chunk=input_view[self._input_offset:self._input_offset+_PIPE_BUF]try:self._input_offset+=os.write(key.fd,chunk)exceptBrokenPipeError:selector.unregister(key.fileobj)key.fileobj.close()else:ifself._input_offset>=len(self._input):selector.unregister(key.fileobj)key.fileobj.close()elifkey.fileobjin(self.stdout,self.stderr):data=os.read(key.fd,32768)ifnotdata:selector.unregister(key.fileobj)key.fileobj.close()self._fileobj2output[key.fileobj].append(data)self.wait(timeout=self._remaining_time(endtime))# All data exchanged. Translate lists into strings.ifstdoutisnotNone:stdout=b''.join(stdout)ifstderrisnotNone:stderr=b''.join(stderr)# Translate newlines, if requested.# This also turns bytes into strings.ifself.encodingorself.errorsorself.universal_newlines:ifstdoutisnotNone:stdout=self._translate_newlines(stdout,self.stdout.encoding,self.stdout.errors)ifstderrisnotNone:stderr=self._translate_newlines(stderr,self.stderr.encoding,self.stderr.errors)return(stdout,stderr)def_save_input(self,input):# This method is called from the _communicate_with_*() methods# so that if we time out while communicating, we can continue# sending input if we retry.ifself.stdinandself._inputisNone:self._input_offset=0self._input=inputifinputisnotNoneand(self.encodingorself.errorsorself.universal_newlines):self._input=self._input.encode(self.stdin.encoding,self.stdin.errors)

[docs]defsend_signal(self,sig):"""Send a signal to the process."""# Skip signalling a process that we know has already died.ifself.returncodeisNone:os.kill(self.pid,sig)

[docs]defterminate(self):"""Terminate the process with SIGTERM """self.send_signal(signal.SIGTERM)

[docs]defkill(self):"""Kill the process with SIGKILL """self.send_signal(signal.SIGKILL)